filter_input

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

filter_input — Nimmt eine Variable von Außen entgegen und filtert sie optional

Beschreibung

filter_input(
    int $type,
    string $var_name,
    int $filter = FILTER_DEFAULT,
    array|int $options = 0
): mixed

Parameter-Liste

type: Eine der INPUT_*-Konstanten.
Warnung
Der Inhalt der zu filternden Superglobalen ist der ursprüngliche "rohe" Inhalt, der von der SAPI bereitgestellt wird, d. h. bevor die Superglobale verändert wurde. Um eine geänderte Superglobale zu filtern, sollte stattdessen filter_var() verwendet werden.
var_name: Der Name einer Variablen, die innerhalb der Superglobalen des betreffenden type gefiltert werden soll.
filter: Der anzuwendende Filter. Dies kann entweder ein Validierungsfilter sein, indem eine der FILTER_VALIDATE_*-Konstanten verwendet wird, ein Bereinigungsfilter, indem eine der FILTER_SANITIZE_*-Konstanten verwendet wird, der Fiter FILTER_UNSAFE_RAW oder ein benutzerdefinierter Filter durch Verwendung von FILTER_CALLBACK.
Hinweis: Die Voreinstellung ist FILTER_DEFAULT, was ein Alias von FILTER_UNSAFE_RAW ist. Dies bedeutet, dass standardmäßig keine Filterung stattfindet.
options: Entweder ein assoziatives array von Optionen oder eine Bitmaske der Filterflag-Konstanten FILTER_FLAG_*. Wenn filter Optionen akzeptiert, können die Flags durch Verwendung des Array-Schlüssels "flags" angegeben werden.

Rückgabewerte

Bei Erfolg wird die gefilterte Variable zurückgegeben. Wenn die Variable nicht gesetzt ist, wird false zurückgegeben. Im Fehlerfall wird false zurückgegeben, es sei denn, das Flag FILTER_NULL_ON_FAILURE wird verwendet; in diesem Fall wird null zurückgegeben.

Beispiele

Beispiel #1 filter_input()-Beispiel

<?php
$search_html = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_SPECIAL_CHARS);
$search_url = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_ENCODED);
echo "Sie haben nach $search_html gesucht.\n";
echo "<a href='?search=$search_url'>Erneut suchen.</a>";
?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

Sie haben nach Ich &#38 Sohn gesucht.
<a href='?search=Ich%20%26%20Sohn'>Erneut suchen.</a>

Siehe auch

filter_input_array() - Nimmt mehrere Variablen von Außen entgegen und filtert sie optional
filter_var() - Filtert eine Variable mit einem angegebenen Filter
filter_var_array() - Nimmt mehrere Variablen entgegen und filtert sie optional
Validierungsfilter FILTER_VALIDATE_*
Bereinigungsfilter FILTER_SANITIZE_*

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User Contributed Notes 9 notes

down

100

CertaiN ¶

10 years ago

This function provides us the extremely simple solution for type filtering.

Without this function...
<?php
if (!isset($_GET['a'])) {
    $a = null;
} elseif (!is_string($_GET['a'])) {
    $a = false;
} else {
    $a = $_GET['a'];
}
$b = isset($_GET['b']) && is_string($_GET['b']) ? $_GET['b'] : '';
?>

With this function...
<?php
$a = filter_input(INPUT_GET, 'a');
$b = (string)filter_input(INPUT_GET, 'b');
?>

Yes, FILTER_REQUIRE_SCALAR seems to be set as a default option. 
It's very helpful for eliminating E_NOTICE, E_WARNING and E_ERROR. 
This fact should be documented.

down

anthony dot parsons at manx dot net ¶

17 years ago

FastCGI seems to cause strange side-effects with unexpected null values when using INPUT_SERVER and INPUT_ENV with this function. You can use this code to see if it affects your server:
<?php
var_dump($_SERVER);
foreach ( array_keys($_SERVER) as $b ) {
    var_dump($b, filter_input(INPUT_SERVER, $b));
}
echo '<hr>';
var_dump($_ENV);
foreach ( array_keys($_ENV) as $b ) {
    var_dump($b, filter_input(INPUT_ENV, $b));
}
?>
If you want to be on the safe side, using the superglobal $_SERVER and $_ENV variables will always work. You can still use the filter_* functions for Get/Post/Cookie without a problem, which is the important part!

down

rimelek at rimelek dot hu ¶

10 years ago

If your $_POST contains an array value:
<?php
$_POST  = array(
    'var' => array('more', 'than', 'one', 'values')
);
?>
you should use FILTER_REQUIRE_ARRAY option:
<?php
var_dump(filter_input(INPUT_POST, 'var', FILTER_DEFAULT , FILTER_REQUIRE_ARRAY));
?>
Otherwise it returns false.

down

ss23 at ss23 dot geek dot nz ¶

14 years ago

Note that this function doesn't (or at least doesn't seem to) actually filter based on the current values of $_GET etc. Instead, it seems to filter based off the original values.
<?php
$_GET['search'] = 'foo'; // This has no effect on the filter_input

$search_html = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_SPECIAL_CHARS);
$search_url = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_ENCODED);
echo "You have searched for $search_html.\n";
echo "<a href='?search=$search_url'>Search again.</a>";
?>

If you need to set a default input value and filter that, use filter_var on your required input variable instead

down

Stefan Weinzierl ¶

10 years ago

Here is an example how to work with the options-parameter. Notice the 'options' in the 'options'-Parameter!

<?php
$options=array('options'=>array('default'=>5, 'min_range'=>0, 'max_range'=>9));

$priority=filter_input(INPUT_GET, 'priority', FILTER_VALIDATE_INT, $options);
?>

$priority will be 5 if the priority-Parameter isn't set or out the given range.

down

chris at chlab dot ch ¶

12 years ago

To use a class method for a callback function, as usual, provide an array with an instance of the class and the method name.
Example:

<?php
class myValidator
{
  public function username($value)
  {
    // return username or boolean false
  }
}

$myValidator = new myValidator;
$options = array('options' => array($myValidator, 'username'));
$username = filter_input(INPUT_GET, 'username', FILTER_CALLBACK, $options);
var_dump($username);
?>

down

akshay dot leadindia at gmail dot com ¶

11 years ago

The beauty of using this instead of directly using filter_var( $_GET['search'] ) is that you don't need to check if( isset( $_GET['search'] ) ) as if you pass that to filter_var and the key is not set then it will result in a warning. This function simplifies this and will return the relevant result to you (as per your options set) if the key has not been set in the user input. 

If the type of filter you are using also supports a 'default' argument then this function will also stuff your missing input key with that value, again saving your efforts

down

travismowens at gmail dot com ¶

14 years ago

I wouldn't recommend people use this function to store their data in a database.  It's best not to encode data when storing it, it's better to store it raw and convert in upon the time of need.

One main reason for this is because if you have a short CHAR(16) field and the text contains encoded characters (quotes, ampersand) you can easily take a 12 character entry which obviously fits, but because of encoding it no longer fits.

Also, while not as common, if you need to use this data in another place, such as a non webpage (perhaps in a desktop app, or to a cell phone SMS or to a pager) the HTML encoded data will appear raw, and now you have to decode the data.

In summary, the best way to architect your system, is to store data as raw, and encode it only the moment you need to.  So this means in your PHP upon doing a SQL query, instead of merely doing an   echo $row['title']  you need to run htmlentities() on your echos, or better yet, an abstract function.

down

HonzaZ ¶

2 years ago

In fastcgi sapi implementations, filter_input(INPUT_SERVER) can return empty results.

In my case (8.1.9 64bit php-cgi) it was caused by auto_globals_jit enabled . When disabled (in php.ini on php startup), filter_input(INPUT_SERVER) works correctly.

php-fpm sapi isn't affected.

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